dest argument to add_argument is Optional (#2040)

argparse.py checks for None in _get_optional_kwargs.

Author: JelleZijlstra

stdlib/2and3/argparse.pyi

@@ -62,7 +62,7 @@ class _ActionsContainer:
                      required: bool = ...,
                      help: _Text = ...,
                      metavar: Union[_Text, Tuple[_Text, ...]] = ...,
-                     dest: _Text = ...,
+                     dest: Optional[_Text] = ...,
                      version: _Text = ...) -> Action: ...
     def add_argument_group(self, *args: Any, **kwargs: Any) -> _ArgumentGroup: ...
     def add_mutually_exclusive_group(self, **kwargs: Any) -> _MutuallyExclusiveGroup: ...